In the background art, a stretchable sheet may be used as an exterior material of a diaper, which is an example of an absorbent article. For example, a composite sheet in which a first sheet in which high stretchability in a longitudinal direction of the first sheet is developed by being drawn in the longitudinal direction and a second sheet having stretchability in a longitudinal direction of the second sheet that is lower than the stretchability of the first sheet are overlapped and joined may be used as the stretchable sheet.
Here, stretchability of this composite sheet is mainly based on the stretchability of the first sheet. Therefore, the first sheet needs to be attached to the second sheet while being in an extended state, and, for example, a method illustrated in a perspective view of FIG. 1 is disclosed as an exemplary method of producing the composite sheet 3S.
That is to say, according to this method, first, stretchability is developed in the first sheet 1S by applying a so-called gear drawing process on the first sheet 1S with gear rolls 121. Then, secondly, the first sheet 1S is extended in a longitudinal direction while being transported and looped around an upstream roll 131 and a downstream roll 141, and the first sheet 1S in an extended state is transported to a joining roll 151 on a downstream side and joined to the second sheet 2S (e.g., see Patent Literature PTL 1).